[MasterChimneyPro]

I notice an intermittent hum just after shutting my diesel down and sometimes while driving. It's usually 3 short "notes". Any clue's?

 

[RDinNHandAZ]

I haven’t noticed it on my van but it may be a solenoid or vacuum valve opening. Have you always had it? I’ll pay better attention. I have to go to Phoenix on Friday so I can check then.

 

[MasterChimneyPro]

I've always had it but it seems more noticeable now. It always happens right after shut down and while stopped for a traffic light and such. I'm wondering if it's the def pump purging the lines.

 

[charity's van]

Mine hums/honks too. I always thought it came from the air filter area

 

[MasterChimneyPro]

Mine hums/honks too. I always thought it came from the air filter area

Hums/honks is a better description-thanks.

 

[stonehopper]

Mine had this to the extreme. In the conditions you described it would moan like a sick duck. It was in that bundle of vaccuume actuators in the middle on top of the engine. You could put your hand on it and feel it vibrate. My dealer replaced it under warranty even though it was still working. Much better now. I can still barely hear it but now it's just doing its job.

 

[Bucho]

I've always had it but it seems more noticeable now. It always happens right after shut down and while stopped for a traffic light and such. I'm wondering if it's the def pump purging the lines.

Mine does this too.
I hear it when I shut the engine off.

 

[RDinNHandAZ]

I feel left out as mine just doesn’t do it! Perhaps I should go in and ask my dealer why mine doesn’t honk?